Curve-scriber.



L. C. F. FERRI.

CURVE SGRIBER.

APPLIoATIoN FILED JUNI: 21, 190s.

1,004, 1 57. Patented Sept. 26, 1911.

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LODOVICO CARLO FRANCESCO FERRI, OF' PARIS, FRANCE.

CURVE-SCRIBER.

To all whom it may concern:

Be it known that I, LoDovIco CARLO FRANCESCO FERRI, a subject of Italy,residing at 27 Rue de Tolbiac, Paris, France, have invented a newCurve-Scriber.

Figure 1 is a plan view of my compass. Fig. 2 is a sectional view online ow?) of Fig. l. Fig. 3 is a side elevation of the movable rule andFig. 8 is a plan view thereof. Fig. 4 is an enlarged plan view of thejointed projection and Fig. 5 is a side view thereof. Fig. 6 is a topview of this jointed portion, showing the locking bolt. Fig. 7 is anenlarged section through one of the grooved portions of the plate withthe guide slides in position.

The compass for tracing an oval, an ellipse, or a circle forming thesubject matter of this invention consists substantially of l. A woodenor' metal plate or frame fr, in which any numb-er of grooves are formed,the section of which is shown in Fig. 2. These grooves are formed by anarc of a circle the center of which is situated on the axis A B and bythe tangent to the circle starting from a point situated beyond thecommon tangent C D at a dis tance from it equal to the diameter of thecircle reduced by -llth The axes A B and C D likewise serve as grooves.The grooved projecting parts c are jointed in the middle by means of ahinge (Figs. 4 and 5) and may be folded as indicated on the left in Fig.1 to atiord a passage for a pencil or drawing-pen while the tracing isbeing effected, or to facilitate the introduction of the apparatus intothe compass-boX- A bolt c clearly shown in Fig. 6 enables the groove tobe set straight and made rigid when this is necessary.

2. A rule f (Fig. 8) made of wood or of metal and which can belengthened or shortened at will for the purpose of tracing curves ofvarious sizes. This rule is composed oftwo pieces the one f carrying adetachable slide being hollow. Lengthwise in the bottom a groove isformed which allows of the displacement of a second slide g. This part.tits into the former and carries at its end a head L with a lengtheningbar intended for receiving the pencil holder or the drawing-pen of anordinary compass. This arrangement enables pencils or draw- Specifcationcf Letters Patent.

Application filed .Tune 21, 1909.

Patented Sept. 26, `1911. Serial No. 503,396.

has three grooves. Each groove serves for tracing an oval of anydetermined size comprised between two limits. In order to trace theoval: the slide at the end of the rule being placed in the groove C Dthe other slide is adjusted at a distance equal to the diameter of thecircle of the groove which it is desired to employ. The pencil or thedrawing-pen being in position, all that is necessary for forming thecurve is to turn the rule.

The ellipse isV formed by the moving of the slides in the grooves A Band C D. In order to prevent the slide z' from engaging in the obliquegrooves, two thin plates Z are placed along the groove A B and forcet-he slide to follow that groove. Fig. 1 shows one of these plates inposition. Fig. 7 illustrates these plates in section and theirpositions. By fixing the slide at the end of the rule at the place wherethe grooves A B and C D intersect each other, the circumference of acircle may likewise be traced.

I'Iaving thus described my invention, what I claim as new and desire tosecure by Letters Patent, is

1. In a compass for tracing ovals, ellipses or circles, a plate providedwith a series of grooves, each formed by an arc of a circle terminatingin straight lines which meet in a line passing through the centers fromwhich said ares are struck, and also with grooves crossing each otherand the curved grooves; a projection at each side of the plate in linewith one of the grooves last named, the extremities of said projectionsbeing hinged and capable ofbeing folded against the projections; aremovable rule adapted to be secured at one end to the plate and, amovable headed rod adjustably secured to said rule and adapted to travelin any one of the grooves; an extension piece slidably adjustable insaid rule and a marker adjust-ably secured in said extension piece.

2. In a compass for describing ovals, el-

lipses or circles, a plate formed with a plurality of curved groovesterminating in straight grooves and also having intersecting' grooves;folding extensions at both sides of the plate; an adjustable rulepivotally secured to said plate; a sliding member on said rule; anadjustable pencil carrying head secured to said sliding member andplates adapted to close the grooves in the plate when desired.

In testimony whereof I affix my signature in presence of two Witnesses.

LODOVIC() CARLO FRANCESCO FERRI. Vtnesses:

DEAN B. MASON, SECTOR MATRAY.

Copies of this patent may be obtained forve cents each, by addressingthe Commissioner of Patents,

' Washington, D. C.

